https://qooah.com/2016/03/17/android-n-%e5%8f%ab%e4%bb%80%e9%ba%bc-google-%e5%85%a7%e9%83%a8%e5%8f%ab%e5%ae%83-%e8%8a%9d%e5%a3%ab%e8%9b%8b%e7%b3%95/